Estimation of rainfall from Ka band altimeter data: computation of waveforms in presence of rain

To prepare future post-Envisar altimetric mission, the French National Space Center (CNES) has invited scientists to investigate the concept of a radar altimeter operating at Ka band (35.75 GHz). This altimeter could be used alone on a micro-satellite or with a dual frequency (Ku-C band) altimeter on a future JASON-n mission. At Ka band, cloud liquid water and precipitation can strongly attenuate the signal even for light rain. It is thus important to analyze thoroughly the impact of rain on Ka band altimeter measurement, firstly to identify the samples possibly affected by rain to correct them or eliminate them from further processing, secondly to give, if possible, an estimate of rain fall rate or rain cell characteristics. A new method of computation of altimeter waveforms in presence of strong attenuation is presented